In recent years, handheld computers (and other portable and/or handheld electronic devices) have become increasingly widely used. Since the dividing lines between handheld computers and other handheld electronic devices (e.g., PDAs, wireless IM devices, cell phones, test equipment and pagers) are not clear, we generically refer to all such computers and devices as handheld electronic devices.
Handheld electronic devices frequently include a keyboard for user input and nearly always include a display for providing visual information to a user. It is often desirable for handheld electronic devices to have two (or more) mechanical configurations. In one configuration, the keyboard is exposed for user input and the display is visible. In a second configuration, the keyboard is covered, but the display is still visible. The main motivation for providing such multiple mechanical configurations is to reduce the physical size of the handheld electronic device. This strategy is effective because the keyboard and display are relatively large parts of a handheld electronic device, and are not amenable to straightforward miniaturization. For example, a small keyboard can be difficult to use, and a small display can be difficult to read and can provide only a small amount of information.
The desirability of providing such mechanical configurations of a handheld electronic device has been recognized, and accordingly several approaches have been considered in the art. For example, U.S. Pat. No. 6,665,173 considers a handheld electronic device having a display that slides (or pivots) in a plane to cover and uncover a keyboard. U.S. Pat. No. 6,636,419 considers devices where the display slides in a plane or simultaneously slides and tilts up to uncover a keyboard. U.S. Pat. No. 6,016,176 considers a handheld device having a flexible display that can wrap about the body of the device. The device of U.S. Pat. No. 5,241,303 has a detachable keyboard which can be disposed in two positions, one covered and the other exposed.
A relatively simple mechanical configuration is a display which slides in a plane to cover and uncover the keyboard (e.g., as in U.S. Pat. No. 6,665,173). However, some care is often required in operating devices having this configuration, to avoid mechanical binding of the sliding joint(s) of the device. This problem of mechanical binding of sliding joints is not recognized in the above-cited references, and so these references also provide no solutions to this problem.
Accordingly, it would be an advance in the art to provide a handheld electronic device having a slidable display which does not bind when being moved.